Displaying 20 results from an estimated 2000 matches similar to: "natural splines"
2003 May 23
2
predict.smooth.spline
I'm using R 1.7.0 on linux. With this version of R the package modreg is
automatically loaded at start of session. However attempting to use
predict.smooth.spline() produces Error: couldn't find function
predict.smooth.spline.
The function smooth.spline() is OK. What am I missing?
======================================
I.White
ICAPB, University of Edinburgh
Ashworth Laboratories, West
2002 Aug 22
1
aov bug? (PR#1930)
R : Copyright 2001, The R Development Core Team
Version 1.4.0 (2001-12-19)
R is free software and comes with ABSOLUTELY NO WARRANTY.
You are welcome to redistribute it under certain conditions.
Type `license()' or `licence()' for distribution details.
R is a collaborative project with many contributors.
Type `contributors()' for more information.
Type `demo()' for some demos,
2005 Feb 10
1
Failure of update.packages()
Can anyone explain why with latest version of R (2.0.1) on FC3, installed
from R-2.0.1-0.fdr.2.fc3.i386.rpm, update.packages() produces the message
/usr/lib/R/bin/Rcmd exec: INSTALL: not found.
Indeed /usr/lib/R/bin seems to lack various shell scripts (INSTALL,
REMOVE, etc).
======================================
I.White
University of Edinburgh
Ashworth Laboratories, West Mains Road
Edinburgh
2003 Sep 07
3
bug in crossprod? (PR#4092)
# Your mailer is set to "none" (default on Windows),
# hence we cannot send the bug report directly from R.
# Please copy the bug report (after finishing it) to
# your favorite email program and send it to
#
# r-bugs@r-project.org
#
######################################################
# The last line of following code produces a segmentation fault:
x <- 1:10
f <- gl(5,2)
2003 Jul 22
2
animal models and lme
Hi,
You should look at Pinheiro and Bates (2000) Mixed-effects models in S and S-Plus. It describes how to format the correlation matrix to pass to functions lme and gls. Basically, the correlation matrix has to be one of the corStruct classes, probably corSymm for your example. So in the call to lme (or gls if you really have no random effects), use something like:
2005 May 26
1
specifying values in correlation matrix in nlme
Could anyone help with a linear mixed model fitting problem ?
The model is :
Y= Xp + Zu + e
where X, Z are known design matrix, p is fixed effect factor, u is
random effect, u~ (0, G) , e~(0,R)
The main problem is , I want to fix the covariance matrix G to be a
constant times a known covariance matrix A, G = c*A (c is positive
constant, A is a predefined matrix with values manually set by
2013 Mar 11
1
Use pcls in "mgcv" package to achieve constrained cubic spline
Hello everyone,
Dr. wood told me that I can adapting his example to force cubic spline to pass through certain point.
I still have no idea how to achieve this. Suppose we want to force the cubic spline to pass (1,1), how can
I achieve this by adapting the following code?
# Penalized example: monotonic penalized regression spline .....
# Generate data from a monotonic truth.
2007 Dec 07
1
Make natural splines constant outside boundary
Hi,
I'm using natural cubic splines from splines::ns() in survival
regression (regressing inter-arrival times of patients to a queue on
queue size). The queue size fluctuates between 3600 and 3900.
I would like to be able to run predict.survreg() for sizes <3600 and
>3900 by assuming that the rate for <3600 is the same as for 3600 and
that for >4000 it's the same as for
2010 Jun 11
1
Documentation of B-spline function
Goodmorning,
This is a documentation related question about the B-spline function in R.
In the help file it is stated that:
"df degrees of freedom; one can specify df rather than knots; bs() then chooses df-degree-1 knots at suitable quantiles of x (which will ignore missing values)."
So if one were to specify a spline with 6 degrees of freedom (and no intercept) then a basis
2011 Sep 06
1
Question about Natural Splines (ns function)
Hi - How can I 'manually' reproduce the results in 'pred1' below? My attempt
is pred_manual, but is not correct. Any help is much appreciated.
library(splines)
set.seed(12345)
y <- rgamma(1000, shape =0.5)
age <- rnorm(1000, 45, 10)
glm1 <- glm(y ~ ns(age, 4), family=Gamma(link=log))
dd <- data.frame(age = 16:80)
mm <- model.matrix( ~ ns(dd$age, 4))
pred1 <-
2009 Sep 20
1
How to choose knots for GAM?
Hi, all
I want to choose same knots in GAM for 10 different studies so that they has
the same basis function. Even though I choose same knots and same dimensions
of basis smoothing, the basis representations are still not same.
My command is as follows:
data.gam<-gam(y~s(age,bs='cr',k=10)+male,family=binomial,knots=list(age=seq(45,64,length=10)))
What is my mistake for choice of
2002 Aug 16
2
[nlme] BLUPs for a new subject in a fitted lme model?
I am seeking for a method to calculate, given a fitted lme model
and some data for a subject, the random effects predictors
for this subject. I can only find predictors for the subjects used in
creating the fit. Of course I could just add the subject and redo the fit.
But I want to avoid just this refitting.
Thanks for help
wbk
2011 May 04
1
natural cubic splines
Dear R-helpers,
I need to fit natural cubic spline with specified number of knots. I
expected 'splines' package will be helpful, but I am confused by its
help. Is more detailed documentation available for it or could you
recommend another R function?
Best regards
Ondrej Mikula
2004 Oct 27
1
se.contrast
After a one-way anova, se.contrast computes the standard error of a
contrast, but not the value of the contrast itself. Wouldn't this be
useful? Am I missing something?
======================================
I.White
ICAPB, University of Edinburgh
Ashworth Laboratories, West Mains Road
Edinburgh EH9 3JT
Fax: 0131 650 6564 Tel: 0131 650 5490
E-mail: iwhite at staffmail.ed.ac.uk
2005 Apr 14
1
LOCFIT: What's it doing?
Dear R-users,
One of the main reasons I moved from GAUSS to R (as an econometrician) was because of the existence of the library LOCFIT for local polynomial regression. While doing some checking between my former `GAUSS code' and my new `R code', I came to realize LOCFIT is not quite doing what I want. I wrote the following example script:
2005 Feb 01
3
polynomials REML and ML in nlme
Hello everyone,
I hope this is a fair enough question, but I don’t have access to a copy
of Bates and Pinheiro. It is probably quite obvious but the answer might
be of general interest.
If I fit a fixed effect with an added quadratic term and then do it as
an orthogonal polynomial using maximum likelihood I get the expected
result- they have the same logLik.
2010 Apr 19
0
Natural cubic splines produced by smooth.Pspline and predict function in the package "pspline"
Hello,
I am using R and the smooth.Pspline function in the pspline package to
smooth some data by using natural cubic splines. After fitting a
sufficiently smooth spline using the following call:
(ps=smooth.Pspline(x,y,norder=2,spar=0.8,method=1)
[the values of x are age in years from 1 to 100]
I tried to check that R in fact had fitted a natural cubic spline by
checking that the resulting
2008 Jan 01
3
Specify a correct formula in R for Piecewise Linear Functions?
Dear all,
I have two variables, y and x. It seems that the relationship between them
is Piecewise Linear Functions. The cutpoint is 20. That is, when x<20, there
is a linear relationship between y and x; while x>=20, there is another
different linear relationship between them.
How can i specify their relationships in R correctly?
# glm(y~I(x<20)+I(x>=20),family = binomial, data =
2011 Sep 20
2
Multivariate spline regression and predicted values
Hello,
I am trying to estimate a multivariate regression of Y on X with
regression splines. Y is (nx1), and X is (nxd), with d>1. I assume the
data is generated by some unknown regression function f(X), as in Y =
f(X) + u, where u is some well-behaved regression error. I want to
estimate f(X) via regression splines (tensor product splines). Then, I
want to get the predicted values for some new
2009 Feb 25
1
monotonic GAM with more than one term
Hi,
Does anyone know how to fit a GAM where one or more smooth terms are
constrained to be monotonic, in the presence of "by" variables or
other terms? I looked at the example in ?pcls but so far have not been
able to adapt it to the case where there is more than one predictor.
For example,
require(mgcv)
set.seed(0)
n<-100
# Generate data from a monotonic truth.